Website DailyTech took a sample of the XTX card with a core clock of 750MHz and 1GB of GDDR 4 clocked to 2020MHz and ran it against an Nvidia GeForce 8800 GTX. For comparison it also re-tested the 745MHz core, 800MHz memory Radeon HD 2900 XT, equipped with 512MB of GDDR 3.

The bottom line: on the basis of these tests at least, the XTX doesn't provide much of an advantage over the XT. Since the core clock speed difference is just 5MHz, and the two GPUs are otherwise identical, clearly the gain - typically amounting to less than two extra frames a second - comes from the extra 512MB of GDDR 4.

Watch out for Register Hardware's full review of the AMD ATI Radeon HD X2900 series next month.